On Thu, 30 Jun 2011 15:00:46 -0700 (PDT), Gene wrote in message
<alpine.LFD.2.00.1106301459220.4148@...>:
> On Thu, 30 Jun 2011, Torsten Dreyer wrote:
>
> > Hi all,
> >
> > The conversion into a static simulator will take place at my house
> > some 60km south of the airfield, so we will start slicing the bird
> > into smaller chunks for transportation on a truck. This will happen
> > very soon and I fear, it will be the heart-breaking part of this
> > story.
> >
> I would recommend you do your disassembly very carefully as you'll be
> able to recoup your costs by selling off the parts you don't need!
> The wings & tail should help pay for the whole thing by themselves. :)
..which diesel, the Thielert 135 hp conversion? It has been
certified STC-style as "normal GA", or as "Experimental"?
We have this engine properly modeled in FG?
> Congrats and great job guys!
>
> g.
..here Gene makes very good sense. ;o)
--
..med vennlig hilsen = with Kind Regards from Arnt Karlsen
...with a number of polar bear hunters in his ancestry...
Scenarios always come in sets of three:
best case, worst case, and just in case.

On Thu, 30 Jun 2011, Torsten Dreyer wrote:
> Hi all,
>
> The conversion into a static simulator will take place at my house some 60km
> south of the airfield, so we will start slicing the bird into smaller chunks
> for transportation on a truck. This will happen very soon and I fear, it will
> be the heart-breaking part of this story.
>
I would recommend you do your disassembly very carefully as you'll be able
to recoup your costs by selling off the parts you don't need! The wings &
tail should help pay for the whole thing by themselves. :)
Congrats and great job guys!
g.
--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
http://www.simpits.org/geneb - The Me-109F/X Project
Some people collect things for a hobby. Geeks collect hobbies.
ScarletDME - The red hot Data Management Environment
A Multi-Value database for the masses, not the classes.
http://www.scarletdme.org - Get it _today_!
Political correctness is a doctrine, fostered by a delusional, illogical
minority, and rabidly promoted by an unscrupulous mainstream media, which
holds forth the proposition that it is entirely possible to pick up a turd
by the clean end.

Hi all,
some time ago, Martin announced some special hardware for our FlightGear
presentations at FSweekend and LinuxTag. Today, after several month of mostly
bureaucratic adventures, he managed to ferry our new toy across roughly half
of Germany. This is even more noticeable given the fact, that after several
very hot summer days, an intense cold front passed by the last night and left
behind some low clouds and local showers. Martin managed to stay safely VFR
and find the small grass runway of Wahlstedt (EDHW) in Northern Germany with
just basic navigation equipment (no GPS!) after a little more than two hours
of flight time. He completed his flight in style with an excellent and smooth
landing, ignoring the sometimes gusty winds which are so common in this area.
He was welcomed by Alexa and Torsten with a landing beer of a local brewery
("Beugelbuddelbier") and his copy of our famous FlightGear landing
certificates.
The conversion into a static simulator will take place at my house some 60km
south of the airfield, so we will start slicing the bird into smaller chunks
for transportation on a truck. This will happen very soon and I fear, it will
be the heart-breaking part of this story.
Our goal is to be able to present it later in several options of completeness:
- complete aircraft
- just the fuselage, wing and elevator removed
- just the cabin, no wing or elevator, fuselage cut behind the rear window
- the cabin with wing, fuselage cut behind the rear window
The instruments will be replaced by TFT displays and certainly all controls
will be functional, I'd even love to see the control surface move, have force-
feedback and (dreaming...)
We will keep you updated on the progress...
Here are a few images of day #1 of our new project:
http://www.t3r.de/d-eeqa/
Greetings, Torsten

On Friday 17 June 2011 01:30:45 Erik Hofman wrote:
> On Thu, 2011-06-16 at 22:23 -0500, Jon S. Berndt wrote:
> > I am very close to committing the new atmosphere code (and the new
> > FGWinds) to JSBSim cvs. However, it would be prudent to first get a
> > glitch or two fixed and then grab that code and put that in FlightGear
> > first, just in case the newer atmosphere and winds code causes problems.
>
> Alright, the current state of JSBSim has been pushed to FlightGear GIT.
>
> Erik
There have been a few bug fixes to JSBSim since this sync, notably:
src/FDM/JSBSim/models/flight_control/FGActuator.cpp
src/FDM/JSBSim/models/flight_control/FGFCSComponent.cpp
src/FDM/JSBSim/models/flight_control/FGFCSComponent.h
src/FDM/JSBSim/models/flight_control/FGSwitch.cpp
src/FDM/JSBSim/models/propulsion/FGTank.cpp
We don't want a whole-sale sync but if these six files were updated, that
would be great.
Thanks,
Ron

Thorsten wrote:
> -----Original Message-----
> From:.i.renk@... [mailto:thorsten.i.renk@...]
> Sent: 30 June 2011 13:21
> To: FlightGear developers discussions
> Subject: Re: [Flightgear-devel] A couple of random oddities
>
> > Further research indicates that the F1A, modeled here was NOT capable of
> > M2.0 at 36000ft. M1.9 seem more likely. Moreover, due to structural and
> > stability problems the F1A was operationally limited to M1.7 or
> > approximately 700KIAS. We have pushed a small change in Mach drag to
> > model this better. Ron will look at the Mach stability issue a bit
> later.
>
> I plead guilty - yes, it seems I overlooked the mark...
>
> Still, I think some discrepancy remains, and thanks to everyone for
> looking into it! The Lightning really is a great model.
>
We think it's pretty close now in Git - apart from stability - see what you
think. But it was well worth revisiting, so thanks for the heads-up.
Vivian

> Further research indicates that the F1A, modeled here was NOT capable of
> M2.0 at 36000ft. M1.9 seem more likely. Moreover, due to structural and
> stability problems the F1A was operationally limited to M1.7 or
> approximately 700KIAS. We have pushed a small change in Mach drag to
> model this better. Ron will look at the Mach stability issue a bit later.
I plead guilty - yes, it seems I overlooked the mark...
Still, I think some discrepancy remains, and thanks to everyone for
looking into it! The Lightning really is a great model.
* Thorsten

I've just placed an updated version of Local Weather online. This version
doesn't contain any genuinely new features but fixes one timing problem in
loading the Nasal modules and a couple of issues which have been bugging
me for some time (some improved textures, a couple of cloud model changes,
smooth instaed of hard visibiliuty transitions, an updated
documentation,...) - for a detailed list please see the forum:
http://www.flightgear.org/forums/viewtopic.php?f=5&t=7358&start=375
I've also removed all 'Test' entries in the menu structure. If any of
these changes qualfies as violating the feature freeze idea, please let me
know and I see what I can undo.
If someone would be so kind as to pick up that version - I think (hope)
that this is my shot at a version ready for the release. I've been
test-flying it in various modes the last 5 days and not seen any fishy
issues, so I keep my fingers crossed.
In addition, I've noticed that the files
Docs/README.local_weather (*not* Docs/README.local_weather.html!)
and
Models/Weather/stratus_textures_bak.rgb
are obsolete and can be removed.
Thanks in advance!
* Thorsten

On Wed, 29 Jun 2011 23:28:42 +0100
"Vivian Meazza" <vivian.meazza@...> wrote:
> Further research indicates that the F1A, modeled here was NOT capable of
> M2.0 at 36000ft. M1.9 seem more likely. Moreover, due to structural and
> stability problems the F1A was operationally limited to M1.7 or
> approximately 700KIAS. We have pushed a small change in Mach drag to model
> this better. Ron will look at the Mach stability issue a bit later.
Thanks Vivian (and Ron)... It's been so long since I did the model that I've forgotten all the relevant figures; I know it matched all the descriptions of flight behaviour I could get hold of at the time fairly well, but I've not really flown the model since then. There's probably more performance data available for the later marks which is possible confusing people.
Cheers,
AJ

I wrote:
> > -----Original Message-----
> > From: AJ MacLeod [mailto:aj-lists@...]
> > Sent: 29 June 2011 12:51
> > To: FlightGear developers discussions
> > Subject: Re: [Flightgear-devel] A couple of random oddities
> >
> > On Wed, 29 Jun 2011 10:39:55 +0100
> > Vivian Meazza wrote:
> >
> > > > * English Electric Lightning: I believe the plane should be able to
> > reach
> > > > Mach 2 around 36.000 ft in level flight - even in a descending
> > pattern, I
> > > > was never able to reach above Mach 1.7 - is there a problem with the
> > FDM?
> > > The author is inactive at the moment. Perhaps he can be persuaded to
> > give
> > > this fine model a bit of a work-over.
> >
> > The author is a bit too active, which sadly doesn't leave any time for
> > Flightgear :-( The instruments I'll try and fix myself, but do any
> JSBSim
> > experts have any ideas on what might have changed the behaviour of the
> FDM
> > model? It worked OK "before"... though I have no idea when that
> changed.
> >
> > Cheers,
> >
>
> Good to see that you're busy in RL, but not too busy to ignore FG
> completely. I've just pushed Ron's update to the JSBSim config. It needs
> quite a bit of up-elevator trim to maintain the cruise at 36000 ft, so
> there
> might be something else not quite right, but it will do M2.0 at 36000 ft.
>
Further research indicates that the F1A, modeled here was NOT capable of
M2.0 at 36000ft. M1.9 seem more likely. Moreover, due to structural and
stability problems the F1A was operationally limited to M1.7 or
approximately 700KIAS. We have pushed a small change in Mach drag to model
this better. Ron will look at the Mach stability issue a bit later.
Vivian

> -----Original Message-----
> From: AJ MacLeod [mailto:aj-lists@...]
> Sent: 29 June 2011 12:51
> To: FlightGear developers discussions
> Subject: Re: [Flightgear-devel] A couple of random oddities
>
> On Wed, 29 Jun 2011 10:39:55 +0100
> Vivian Meazza wrote:
>
> > > * English Electric Lightning: I believe the plane should be able to
> reach
> > > Mach 2 around 36.000 ft in level flight - even in a descending
> pattern, I
> > > was never able to reach above Mach 1.7 - is there a problem with the
> FDM?
> > The author is inactive at the moment. Perhaps he can be persuaded to
> give
> > this fine model a bit of a work-over.
>
> The author is a bit too active, which sadly doesn't leave any time for
> Flightgear :-( The instruments I'll try and fix myself, but do any JSBSim
> experts have any ideas on what might have changed the behaviour of the FDM
> model? It worked OK "before"... though I have no idea when that changed.
>
> Cheers,
>
Good to see that you're busy in RL, but not too busy to ignore FG
completely. I've just pushed Ron's update to the JSBSim config. It needs
quite a bit of up-elevator trim to maintain the cruise at 36000 ft, so there
might be something else not quite right, but it will do M2.0 at 36000 ft.
Regards,
Vivian

On Wednesday 29 June 2011 05:51:07 AJ MacLeod wrote:
> On Wed, 29 Jun 2011 10:39:55 +0100
>
> Vivian Meazza wrote:
> > > * English Electric Lightning: I believe the plane should be able to
> > > reach Mach 2 around 36.000 ft in level flight - even in a descending
> > > pattern, I was never able to reach above Mach 1.7 - is there a problem
> > > with the FDM?
> >
> > The author is inactive at the moment. Perhaps he can be persuaded to give
> > this fine model a bit of a work-over.
>
> The author is a bit too active, which sadly doesn't leave any time for
> Flightgear :-( The instruments I'll try and fix myself, but do any JSBSim
> experts have any ideas on what might have changed the behaviour of the FDM
> model? It worked OK "before"... though I have no idea when that changed.
>
> Cheers,
>
> AJ
I don't know of any changes that would have impacted your model. We did fix
the thrust tables a few months back... Its really hard for me to see
individual aircraft histories in git, but we probably fixed the elevator drag
issue in this FDM as well. If you remember, aeromatic configured CDde to go
negative at times causing false thrust.
I looked at this model in JSBSim stand-alone and saw three sources of drag at
mach 2.06 and 36,000 ft:
aero/coefficient/CDalpha = 12993.134843 (pounds force)
aero/coefficient/CDmach = 5197.253937 (pounds force)
aero/coefficient/CDde = 8567.342560 (pounds force)
A combined 26,700 pounds of drag.
Our two engines in full reheat at mach 2.06, 36,000 feet put out a combined
thrust of 20,200 pounds of thrust. Leaving 6,500 pounds of drag unbalance, so
we slow down.
The CDde coefficient is 0.04 * |elevator-pos-norm|. This is an aeromatic
default value for all aircraft. Since the Lightening F.1a has an all moving
tailplane not an elevator, this number is way too big. Changing it to 0.008
yields an output of:
aero/coefficient/CDde = 1787.161206 (pounds force)
Or a combined 20,000 pounds of drag. Just about matching what our engines
produce.
Thanks,
Ron

OK,
I tracked this, I am answering myself for the record.
On my system, I had to recompile OSG.
It seems on left-shift-key release, Xorg sends a release event with a wrong
keysym (XK_ISO_Prev_Group instead of XK_Shift_L).
Same thing for right shift key. On release, the X11 keysym is
XK_ISO_Next_Group instead of XK_Shift_R.
So i remap these in OSG through the _extendedKeymap of GraphicsWindowX11.
I add the following remappings in GraphicsWindowX11.cpp of osgViewer:
_extendedKeymap[XK_ISO_Prev_Group] =
osgGA::GUIEventAdapter::KEY_Shift_L;
_extendedKeymap[XK_ISO_Next_Group] =
osgGA::GUIEventAdapter::KEY_Shift_R;
Not sure this is the correct solution, though. It works for me.
Maybe this concerns OSG people? Xorg people?
Cheers,
Sylvain.
On Tue, Jun 28, 2011 at 7:23 PM, Sylvain Mazet <sylvain.mazet@...>wrote:
> Hi all,
>
> First things first: I am a long time user of FlightGear (for play),
> I just love it.
>
> Since using FlightGear-2.0.0, I have a keyboard problem.
>
> Keyboard responds OK, except that the shift modifier,
> once activated, stays on forever.
> Example:
> 1) I start FlightGear,
> 2) I press 'x', I zoom in OK,
> 3) I press 'shift-x', I zoom out OK,
> 4) I press 'x', nothing happens. The shift modifier
> is still there (I activated the "dump" in keyboard.xml to see this).
>
> My system is an up-to-date Debian Linux Squeeze. I use gnome.
>
> I tried:
> - Simgear/FlightGear-2.0.0 bundle
> - Simgear/FlightGear git version (of yesterday: 2.3.0-something)
> - OpenSceneGraph 2.8.2, and latest 3.0.0 (I am not sure it has anything to
> do with it)
>
> I'll continue my investigations, but I could use some help...
> I am posting in case anybody has seen this behavior.
> I cannot find it described in the lists.
>
> Thanks for reading!
>
> Sylvain Mazet.
>

On Wed, 29 Jun 2011 10:39:55 +0100
Vivian Meazza wrote:
> > * English Electric Lightning: I believe the plane should be able to reach
> > Mach 2 around 36.000 ft in level flight - even in a descending pattern, I
> > was never able to reach above Mach 1.7 - is there a problem with the FDM?
> The author is inactive at the moment. Perhaps he can be persuaded to give
> this fine model a bit of a work-over.
The author is a bit too active, which sadly doesn't leave any time for Flightgear :-( The instruments I'll try and fix myself, but do any JSBSim experts have any ideas on what might have changed the behaviour of the FDM model? It worked OK "before"... though I have no idea when that changed.
Cheers,
AJ
--

Thorsten wrote
>
>
> A bunch of issues I've seen - maybe some folks want to fix them before the
> release (all in a GIT pull of 5 days ago):
>
> * The B29 (JSBSim) doesn't run, but rather prints out an error message
>
>
> YOU HAVE AN INCOMPATIBLE CFG FILE FOR THIS AIRCRAFT. RESULTS WILL BE
> UNPREDICTABLE !!
> Current version needed is: 2.0
> You have version:
>
>
> True, but if it is incompatible with 2.4, then it should either be updated
> or removed.
>
Yup - Ron Jenson is on the case - we should be able to push an updated
version soon.
> * English Electric Lightning: I believe the plane should be able to reach
> Mach 2 around 36.000 ft in level flight - even in a descending pattern, I
> was never able to reach above Mach 1.7 - is there a problem with the FDM?
> In addition, the ambient/diffuse setting of the instruments on the main
> panel appears a bit odd - see my pics in the forum
>
> http://www.flightgear.org/forums/viewtopic.php?f=4&t=11930&start=15
The author is inactive at the moment. Perhaps he can be persuaded to give
this fine model a bit of a work-over.
> * Precipitation: A really exotic one (not really relevant in practice, but
> might point to an underlying issue): I sometimes log on from my main user
> account to my fgfs development account on my laptop via su. This works
> fine, except that sound and a lot of hardware 3d acceleration is absent,
> but for quick checks and these things is just fine. Except if there's
> precipitation of any kind - that causes an immediate segmentation fault
> whereas all other 'fancy' effects simply don't run.
>
> * F-16: My sidewinders are a deep blue in external view (looks very odd) -
> the AMRAAM coming with the USAF livery are fine though...
>
> * A380: After reading all the documentation and trying for 3 hours to
> figure out the AP, I conclude that either I don't understand a thing, or
> the AP is plain buggy. I can fly the plane just fine with the AP in
> 'selected' mode, but when I select a VOR radial, bring the plane roughly
> on it and press 'loc' it doesn't follow the radial but gues 'loco', i.e.
> starts a high bank angle turn somewhere (I couldn't figure out where),
> loses altitude rapidly and so on. Also, switching the AP off doesn't
> return the plane in any stable mode such that it would rougly continue
> what it did before, but my usual experience is that throttle gets set very
> low and the plane starts a dive, from which I then have to recover. Also,
> when I set the AP to acquire a given altitude, and then change heading
> during climb, the set altitude is frequently lost and needs to be reset.
>
> It's a bit of a pity, because I can see there has been so much work going
> into this plane. May I suggest here to at least
>
> - disable any menu options of the AP which are not supposed to be used
> - expand the documentation of the system somewhat
>
>
> * X15 - I seem unable to start the engine.
>
> * Twin Otter (dhc6): Does the propeller pitch lever do anything? Somehow,
> I don't notice any effect...
>
> * Piper Comanche 250: If I set the engine mixture to 'full rich' at
> ~17.000 ft altitude - shouldn't the engine die? See my report here
> http://www.flightgear.org/forums/viewtopic.php?f=4&t=11930
>
>
>
Thanks for the work.
Vivian

A bunch of issues I've seen - maybe some folks want to fix them before the
release (all in a GIT pull of 5 days ago):
* The B29 (JSBSim) doesn't run, but rather prints out an error message
YOU HAVE AN INCOMPATIBLE CFG FILE FOR THIS AIRCRAFT. RESULTS WILL BE
UNPREDICTABLE !!
Current version needed is: 2.0
You have version:
True, but if it is incompatible with 2.4, then it should either be updated
or removed.
* English Electric Lightning: I believe the plane should be able to reach
Mach 2 around 36.000 ft in level flight - even in a descending pattern, I
was never able to reach above Mach 1.7 - is there a problem with the FDM?
In addition, the ambient/diffuse setting of the instruments on the main
panel appears a bit odd - see my pics in the forum
http://www.flightgear.org/forums/viewtopic.php?f=4&t=11930&start=15
* Precipitation: A really exotic one (not really relevant in practice, but
might point to an underlying issue): I sometimes log on from my main user
account to my fgfs development account on my laptop via su. This works
fine, except that sound and a lot of hardware 3d acceleration is absent,
but for quick checks and these things is just fine. Except if there's
precipitation of any kind - that causes an immediate segmentation fault
whereas all other 'fancy' effects simply don't run.
* F-16: My sidewinders are a deep blue in external view (looks very odd) -
the AMRAAM coming with the USAF livery are fine though...
* A380: After reading all the documentation and trying for 3 hours to
figure out the AP, I conclude that either I don't understand a thing, or
the AP is plain buggy. I can fly the plane just fine with the AP in
'selected' mode, but when I select a VOR radial, bring the plane roughly
on it and press 'loc' it doesn't follow the radial but gues 'loco', i.e.
starts a high bank angle turn somewhere (I couldn't figure out where),
loses altitude rapidly and so on. Also, switching the AP off doesn't
return the plane in any stable mode such that it would rougly continue
what it did before, but my usual experience is that throttle gets set very
low and the plane starts a dive, from which I then have to recover. Also,
when I set the AP to acquire a given altitude, and then change heading
during climb, the set altitude is frequently lost and needs to be reset.
It's a bit of a pity, because I can see there has been so much work going
into this plane. May I suggest here to at least
- disable any menu options of the AP which are not supposed to be used
- expand the documentation of the system somewhat
* X15 - I seem unable to start the engine.
* Twin Otter (dhc6): Does the propeller pitch lever do anything? Somehow,
I don't notice any effect...
* Piper Comanche 250: If I set the engine mixture to 'full rich' at
~17.000 ft altitude - shouldn't the engine die? See my report here
http://www.flightgear.org/forums/viewtopic.php?f=4&t=11930
I hope some of that info will be useful!
Cheers,
* Thorsten

A bunch of issues I've seen - maybe some folks want to fix them before the
release (all in a GIT pull of 5 days ago):
* The B29 (JSBSim) doesn't run, but rather prints out an error message
YOU HAVE AN INCOMPATIBLE CFG FILE FOR THIS AIRCRAFT. RESULTS WILL BE
UNPREDICTABLE !!
Current version needed is: 2.0
You have version:
True, but if it is incompatible with 2.4, then it should either be updated
or removed.
* English Electric Lightning: I believe the plane should be able to reach
Mach 2 around 36.000 ft in level flight - even in a descending pattern, I
was never able to reach above Mach 1.7 - is there a problem with the FDM?
In addition, the ambient/diffuse setting of the instruments on the main
panel appears a bit odd - see my pics in the forum
http://www.flightgear.org/forums/viewtopic.php?f=4&t=11930&start=15
* Precipitation: A really exotic one (not really relevant in practice, but
might point to an underlying issue): I sometimes log on from my main user
account to my fgfs development account on my laptop via su. This works
fine, except that sound and a lot of hardware 3d acceleration is absent,
but for quick checks and these things is just fine. Except if there's
precipitation of any kind - that causes an immediate segmentation fault
whereas all other 'fancy' effects simply don't run.
* F-16: My sidewinders are a deep blue in external view (looks very odd) -
the AMRAAM coming with the USAF livery are fine though...
* A380: After reading all the documentation and trying for 3 hours to
figure out the AP, I conclude that either I don't understand a thing, or
the AP is plain buggy. I can fly the plane just fine with the AP in
'selected' mode, but when I select a VOR radial, bring the plane roughly
on it and press 'loc' it doesn't follow the radial but gues 'loco', i.e.
starts a high bank angle turn somewhere (I couldn't figure out where),
loses altitude rapidly and so on. Also, switching the AP off doesn't
return the plane in any stable mode such that it would rougly continue
what it did before, but my usual experience is that throttle gets set very
low and the plane starts a dive, from which I then have to recover. Also,
when I set the AP to acquire a given altitude, and then change heading
during climb, the set altitude is frequently lost and needs to be reset.
It's a bit of a pity, because I can see there has been so much work going
into this plane. May I suggest here to at least
- disable any menu options of the AP which are not supposed to be used
- expand the documentation of the system somewhat
* X15 - I seem unable to start the engine.
* Twin Otter (dhc6): Does the propeller pitch lever do anything? Somehow,
I don't notice any effect...
* Piper Comanche 250: If I set the engine mixture to 'full rich' at
~17.000 ft altitude - shouldn't the engine die? See my report here
http://www.flightgear.org/forums/viewtopic.php?f=4&t=11930
I hope some of that info will be useful!
Cheers,
* Thorsten

Hi all,
First things first: I am a long time user of FlightGear (for play),
I just love it.
Since using FlightGear-2.0.0, I have a keyboard problem.
Keyboard responds OK, except that the shift modifier,
once activated, stays on forever.
Example:
1) I start FlightGear,
2) I press 'x', I zoom in OK,
3) I press 'shift-x', I zoom out OK,
4) I press 'x', nothing happens. The shift modifier
is still there (I activated the "dump" in keyboard.xml to see this).
My system is an up-to-date Debian Linux Squeeze. I use gnome.
I tried:
- Simgear/FlightGear-2.0.0 bundle
- Simgear/FlightGear git version (of yesterday: 2.3.0-something)
- OpenSceneGraph 2.8.2, and latest 3.0.0 (I am not sure it has anything to
do with it)
I'll continue my investigations, but I could use some help...
I am posting in case anybody has seen this behavior.
I cannot find it described in the lists.
Thanks for reading!
Sylvain Mazet.

On Tue, 28 Jun 2011, xsaint wrote:
> Hello Anders,
>
> Yes you are right, after i moved the offset position, the plane do take
> off without sinking into the ground.
> But this give rise to another issue, as long as i am on external views
> (eg chase, fly by views), it renders as if the CG is at the tail. When i
> pitch up/down, the origin seems to be the tail.
>
> I guess the external views are controlled by FG globally, is there a
> variable/node i can manipulate via nasal? As i was flying, i tried to
> change some offset positions on Sim/View node (for chase view), nothing
> seems to move the origin back to the ctr of the plane.
You can offset the target point for external views (which by default is
the origin of the main 3d model coordinate system, not the CG). See for
example Aircraft/Short_Empire/Short_Empire-set.xml:
<!-- Move the center of the external views. -->
<view n="1">
<config>
<target-z-offset-m type="double"> 10.0 </target-z-offset-m>
</config>
</view>
...
Note that your aircraft still rotates around its current CG, the effect
you see is caused by the camera targeting the 3d model coordinate system
origin, which in your case apparently is close to the tail.
Cheers,
Anders
--
---------------------------------------------------------------------------
Anders Gidenstam
WWW: http://www.gidenstam.org/FlightGear/

Hello Anders,
Yes you are right, after i moved the offset position, the plane do take
off without sinking into the ground.
But this give rise to another issue, as long as i am on external views
(eg chase, fly by views), it renders as if the CG is at the tail. When i
pitch up/down, the origin seems to be the tail.
I guess the external views are controlled by FG globally, is there a
variable/node i can manipulate via nasal? As i was flying, i tried to
change some offset positions on Sim/View node (for chase view), nothing
seems to move the origin back to the ctr of the plane.
and Yes, the CG of the plane is at the center as according to YASIM solver
Thank you for your guidance
Cheers
On Monday 27,June,2011 09:29 PM, Anders Gidenstam wrote:
> On Sun, 26 Jun 2011, xsaint wrote:
>
>> Hello All...
>>
>> I am trying to better understand how YASIM calculates its contacts
>> points....
>>
>> 2) Eventhough CG looks like it is in correct place, in YASIM, the plane
>> do sink to the ground before take off. Insufficient lift maybe.... but
>> the back of the fuselage do sink into the runway. As such, as
>> possibility of implementing tail strikes?
>>
>> Much all appreciate all valuable replies and also if you could point me
>> towards any valuable YASIM documents.
> Another thing to check is the alignment between the 3d model and the FDM
> config - make sure that your main (3d) model XML file uses the same origin
> as the FDM config uses. If the 3d model itself uses a different origin
> you will have to apply offsets in the main 3d model XML file to bring it
> in line with the coordinate system of the FDM config. Note that shifting
> the main model origin will affect the locations of views and sounds too.
>
> For JSBSim FDM configs it is possible to move the FDM visual reference
> point, VRP, in the FDM config to match the origin of the main 3d model XML
> file instead, which will not affect the other coordinate systems used in
> FG.
>
> Cheers,
>
> Anders

Thank you Adrian,
You have much cleared my doubts in YASIM with regards to contact point
issues.
As for Gears sinking into the ground, even adding a fake gear was not
much of a help.
Later i got reply from Andres and he was mentioning the origin offset
could be the cause and he seems right on that. I will be replying him on
that soon, please look out for that reply.
Once again, thank you for your valuable input
Much appreciated
Txs
On Monday 27,June,2011 08:56 PM, Adrian Musceac wrote:
> On Sunday, June 26, 2011 17:27:06 xsaint wrote:
>> Hello All...
>>
>> I am trying to better understand how YASIM calculates its contacts
>> points....
>>
> Hi there, I'll try to answer, see below:
>
>
>> 1) As from my experience, the SIM crashes when some part of the wings
>> comes in contact with a building or ground and it does not crash if
>> other parts of the wings hit the ground of a building.The wing
>> specification is correct in FDM as checked againts the blender script.
>> So how does it deduce the contact points?
>>
> There might be a difference between regular collision detection provided by
> the FG engine itself, about which I have no information, and YASim _ground_
> collision detection. The latter is implemented as follows:
> Contact points (internally represented as gear objects but with special
> properties and hardcoded values for friction) are compiled from the wingtips
> and the fore and aft tips of the fuselage. These contact points will hold at
> full compression 10 times the plane's mass.
> So for a conventional airplane there will be two contact points for the
> fuselage (nose and tail), the main wing tips, the tips of the horizontal and
> vertical stabiliser. Any collision detected with these contact points will be
> treated by YASim as a special case of gear collision and compared to the force
> mentioned above.
>
>> 2) Eventhough CG looks like it is in correct place, in YASIM, the plane
>> do sink to the ground before take off. Insufficient lift maybe.... but
>> the back of the fuselage do sink into the runway. As such, as
>> possibility of implementing tail strikes?
>>
> It is possible that either the aft end of the fuselage as defined in XML is
> higher than the lowest part of the model, or that the mass which it has to
> sustain is larger than the spring compression of the contact point can
> sustain. You can try to compensate the first issue by placing a fake gear
> object at the lowest point where the fuselage touches the ground.
>
>> Much all appreciate all valuable replies and also if you could point me
>> towards any valuable YASIM documents.
>>
> There is a technical document floating on the web, can't quite remember where
> but try to google YASim-simnotes.pdf
> Other than that, your best reference is the source code.
> Hope it helps,
>
> Adrian
>
>
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Yes, John (LFSTech.com) has done some very nice work developing code that
will do image warping and edge blending right inside FlightGear which is
very cool. My understanding is we are waiting for Tim to review the changes
and integrate them into the code base.
Regards,
Curt.
On Sun, Jun 26, 2011 at 11:13 PM, John Wojnaroski <castle@...>wrote:
>
> On Sun, 2011-06-26 at 16:38 -0700, Gene Buckle wrote:
> > On Sun, 26 Jun 2011, Torsten Dreyer wrote:
> >
> > > Buenos Dias Ezequiel and welcome aboard!
> > >
> > > We have a fairly complex multi-monitor display setup on our
> presentation
> > > machine. You can find our configuration from last year's FSweekend at
> > > http://wiki.flightgear.org/FSweekend_2010.
> > > In rendering.xml, the first two <camera> entries show how to define
> viewports
> > > within one single window.
> > > You can define the frustum or perspective for each single viewport.
> > > For the correction of the parabolic distortion, I have no idea. But I
> > > remember that there was something presented along with the collimated
> display
> > >
> http://wiki.flightgear.org/FlightGear_Newsletter_November_2010#Amateur_built_collimated_display
> > > Maybe Gene or Tim can chime in here?
> > >
>
> Perhaps you might also look at the March 2011 newsletter.
>
> http://wiki.flightgear.org/FlightGear_Newsletter_March_2011
>
> > I know there was some work done in order to pre-warp the output from FG,
> > but I'm not sure what the status of that is. Because of NThusim+, I
> > wasn't paying that close attention to it (and I should have been).
> >
>
>
>
>
> ------------------------------------------------------------------------------
> All of the data generated in your IT infrastructure is seriously valuable.
> Why? It contains a definitive record of application performance, security
> threats, fraudulent activity, and more. Splunk takes this data and makes
> sense of it. IT sense. And common sense.
> http://p.sf.net/sfu/splunk-d2d-c2
> _______________________________________________
> Flightgear-devel mailing list
> Flightgear-devel@...
> https://lists.sourceforge.net/lists/listinfo/flightgear-devel
>
--
Curtis Olson:
http://www.atiak.com - http://aem.umn.edu/~uav/http://www.flightgear.org - http://gallinazo.flightgear.org